Swans would want to lock him away quickly as a cashed up Eagles (with the likely retirements of Darling and Kennedy in the next 2 years) and Freo will try throw the kitchen sink at Logan.
Darling isn't even 29 yet. I suspect he has another 3 or 4 years left in him. Also West Coast have Oscar Allen coming through who looks very promising.
I am more worried about Fremantle to be honest. They are desperate for a key forward and might be willing to offer McDonald stupid money to request a trade to them.